This proposal seeks to: 1. Evaluate bone allograft transplantation in a genetically defined rat model in order to systemically gather fundamental immunologic information concerning transplantation of vascularized bone allografts. Protocols have been designed to identify manifestations and, perhaps, the focus of the rejection process in the graft and to determine graft-host factors that affect allograft survival. Light microscopy, electron microscopy, and enzyme histochemistry will be employed to evaluate the rejection process; attempts will be made to alter graft antigenicity and evaluate the affect of cyclosporin-A immunosuppression on graft survival with the long-term objective of developing the used of allogeneic tissue in extremity reconstruction. 2. Evaluate the efficacy of free vascularized muscle flap coverage in the treatment of chronic osteomyelitis in a canine model with the objective of clarifying the role of this technique in clinical reconstructive surgery. 3. Evaluate the growth in orthotopically and heterotopically transplanted epiphyseal plates in a primate model in order to attempt to define the possible clinical role of vascularized epiphyseal transplantation in reconstructive surgery for the treatment of radial club hand, tumors involving epithyses of long bones, and the transferring of digits from the foot to the hand for congenital or traumatic conditions in children. 4. Evaluate the feasibility of molded vascularized osteoneogenesis using a titanium chamber. The possibility of producing bone with a predetermined size and shape as well as a defined vascular nutrient stalk would greatly simplify reconstruction of segmental bone defects. The results of this technique will be compared to conventional reconstructive procedures.